HR: 13:40h
AN: SM23C-01 INVITED    [Abstracts]
TI: Solar Energetic Particle Trapping During Geomagnetic Storms
AU: * Hudson, M
EM: mary.hudson@dartmouth.edu
AF: Dartmouth College, Physics & Astronomy Dept., Hanover, NH 03755,
AU: Kress, B
EM: bkress@dartmouth.edu
AF: Dartmouth College, Physics & Astronomy Dept., Hanover, NH 03755,
AU: Blake, J B
EM: JBernard.Blake@aero.org
AF: The Aerospace Corporation, Space Sciences Dept., El Segundo, Ca 90245,
AU: Mazur, J
EM: Joseph.E.Mazur@aero.org
AF: The Aerospace Corporation, Space Sciences Dept., El Segundo, Ca 90245,
AB: The prompt trapping of Solar Energetic Particles (SEPs) in the inner magnetosphere inside of L = 4 has been reported, including protons and heavier ions, in association with high speed interplanetary shocks and Storm Sudden Commencements (SSCs). These observations include the Bastille Day 2000 CME-driven storm as well as two in November 2001, which produced a long-lived new proton belt, as well as trapping of heavy ions up to Fe in all three cases. A survey of such events around the most recent solar maximum, including high altitude measurements from Polar, HEO and ICO satellites along with low altitude measurements from SAMPEX, indicates similarities to the well-studied March 24, 1991 SSC event. In this event, electrons and protons in drift resonance with a magnetosonic impulse were transported radially inward, requiring a source population which is multi-MeV at geosynchronous. A requirement for such shock-induced acceleration is a high-speed CME- shock at 1 AU, which launches a perturbation with comparable velocity inside the magnetosphere. Secondly, there must be a source population which is drift-resonant with the impulse. The CME-shock itself is a source of solar energetic particles, both protons and heavy ions, with higher fluxes and harder spectra associated with faster moving CMEs. A 3D Lorentz integration of SEP trajectories in electric and magnetic fields taken from the Lyon-Fedder-Mobarry (LFM) global MHD model, using solar wind input parameters from spacecraft measurements upstream from the bow shock, has been carried out for two November, 2001 SEP trapping events, and a CME-shock associated with the Halloween 2003 storm period, 29 October, which transported outer zone electrons and trapped solar energetic electrons into around L = 2.5, with little effect on SEPs. These results indicate that an enhancement in solar wind dynamic pressure for these events plays a role in the observed injection of ions (and electrons) to low L-values, as does the extent of the plasmasphere, included in the total density calculation constraining MHD fields. The plasmasphere affects the magnitude and penetration of the induction electric field transporting electrons and ions to low L values. The dawn-dusk asymmetry of the plasmasphere may create an asymmetry in the effectiveness of the inductive electric field impulse on electrons and ions, and from event to event, depending on the state of plasmapause erosion.
DE: 2716 Energetic particles: precipitating
DE: 2720 Energetic particles: trapped
DE: 2774 Radiation belts
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting